Well, then it's a better deal than one of the companies in Los Angeles which at least last summer when I looked (if you weren't buying) had a 20 year minimum lease.
If you don't purchase it outright though and you want to sell your house at a later point before the system is paid off, you either have to pay it off before selling or get the buyer to assume the payments on the system which is seen as a negative. I think this is all true...